Table 4.
Endmember Spectra and Mineral/Rock Matches, by Sample Number
| Endmember | Textural element | Key features and absorptions (μm) | Rock or mineral(s) library match |
|---|---|---|---|
| Vesicular basalt (sample 17) | |||
| Blue | Dark matrix | Low reflectance, flat shape; absorption at 1.05 | Basalt with pyroxene |
| Magenta | White phenocryst | Relative high reflectance, sinusoidal shape; absorption at 1.22 | Plagioclase feldspar |
| Green | Green phenocryst | Broad V-shape; absorption at 1.05 | Diopside |
| Red | Green phenocryst | Broad U-shape; absorption at 1.05 | Olivine |
| Orange | Green phenocryst | Broad U-shape; absorption at 1.05 | Olivine |
| Silicic volcanic breccia (sample 14) | |||
| Magenta | Red cement | Absorption edge at 0.52, peak at 0.76; absorption at 0.94 | Fe oxyhydroxide (goethite or lepidocrocite) |
| Red | Red cement | Absorption edge at 0.52, peak at 0.74; absorption at 0.88 | Hematite |
| Blue | Gray cement | Shallow sinusoidal shape; no absorptions present | Unknown (no diagnostic absorption) |
| Green | White cement | High reflectance, steep positive slope in viz; absorptions at 0.97 and 1.43 | Hydrated mineral (clay, opal-A, or zeolite) |
| Yellow | Light groundmass in clasts | High reflectance, positive slope; absorptions at 0.88, 0.97, and 1.43 | Mix of unknown with hematite and hydrated mineral (clay, opal-A, or zeolite) |
| Purple | Gray wispy laminations in clasts | Positive slope in viz; absorptions at 0.97 and 1.43 | Mix of unknown with hydrated mineral (clay, opal-A, or zeolite) |
| Basaltic volcanic breccia (sample 10) | |||
| Blue | Dark groundmass in clasts | Low reflectance, flat shape; absorption at 1.05 | Basalt with pyroxene |
| Purple | Gray rind on central clast | Broad V-shape; absorption between 0.97 and 1.05 | Augite |
| Magenta | Light gray cement around clasts | Positive slope in viz and negative slope in IR; absorptions between 0.97 and 1.05, 1.43 and 1.52 | Mix of pyroxene and hydrated mineral (zeolite or sulfate) |
| Brown | Light gray/white cement | Steep positive slope in viz and negative slope in IR; absorptions between 0.97 and 1.05, 1.43, and 1.52 | Mix of pyroxene and hydrated mineral (zeolite or sulfate) |
| Green | White cement | Steep positive slope in viz and negative slope in IR; absorptions at 0.97 and 1.43 | Hydrated mineral (clay, opal-A, or zeolite) |
| Light blue | White cement | Steep positive slope in viz and negative slope in IR; absorptions at 0.97, 1.22, 1.43, and 1.52 | Hydrated mineral (zeolite or sulfate) |
| Red | Orange cement | Positive slope; absorption edge at 0.52; peak at 0.81; absorptions at 0.64, 0.94, and 1.43 | Nontronite (minor Fe oxide) |
| Orange | Orange cement | Positive slope; absorption edge at 0.52; peak at 0.81; absorptions at 0.64, 0.97, 1.05, 1.43, and 1.52 | Mix of nontronite, pyroxene, and hydrated mineral (zeolite) |